Dirty Carbs kill a motor

[Beater]

Hi, I just got a 1979 140 horse Merc running after sitting for 7 years. I had the impellor replaced of course but I'm wondering about the carbs. When I first started it the float in the bottom carb stuck so fuel peed out the little hole at the top of the float bowl. After a bit that stopped and the motor ran quite well. My question is can I take it out on the water and see if it runs ok or will dirty carbs possibly ruin the motor. I seem to remember that someone here said that gummed up carbs from sitting can cause the motor to run too lean and burn out. Hate to tear the carbs down if I don't have to.

 

[rodbolt]

Re: Dirty Carbs kill a motor

tear them down. rebuild the fuel pump or pumps as well. the rubber diaphams tend to tear. gasket kits are cheap and cost the same with or without pistons and machine work.

 

[timmathis]

Re: Dirty Carbs kill a motor

Listen to Rodbolt Better safe than sorry !!!!

 

[Laotzu]

Re: Dirty Carbs kill a motor

Mine sat for 4 years and I had varnish in the carbs. Clean em.<br /><br />Jerry

 

[Clams Canino]

Re: Dirty Carbs kill a motor

Clean the carbs and do the pump. A lean-out can melt pistons quickly. Then you'll have to deal with me and it's not pretty.<br /><br />-W

 

[Beater]

Re: Dirty Carbs kill a motor

Well you have me convinced I'd best rebuild but I'm confused as to how dirty carbs would make it run lean. The oil and gas is mixed so it should get equal portions of that correct? Only lean I can think of is too much air and not enough gas/oil? Also even if the carbs are clean can a lean mixture be possible with improper jet<br />setting?

 

[IBFishing]

Re: Dirty Carbs kill a motor

Originally posted by Beater:<br /> I'm confused as to how dirty carbs would make it run lean.

An example would be trash in the main jets, which would cut off some of the fuel to the cylinders. This would cause more air in cylinders causing a lean condition.<br /><br />

Originally posted by Beater:<br /> Also even if the carbs are clean can a lean mixture be possible with improper jet

If you had too small of a jet, the cylinders would not get enough gas mixed with the air causing a lean condition. This effect is reversed if you have too big of a main jet. Too much fuel and not enough air causing the cylinders to run rich.<br />setting?